In the mid 1980s, a work colleague was having to cope with a mother who when decimal currency came in, just told her DH that she didn't understand it and that he would have to deal with all money handling fromthen on, which he did, she did not even have a purse.
Then in 1982 her DH died and she was living alone, still had no idea how the 'new' currency worked, hadn't handled money for over 20 years and he was rushing from Reading to Yorkshire every weekend to do her shopping, setting up accounts where ever he could, so that she could continue to live without having to come to grips wth this currency she had decided she did not understand.